Apparatus for producing asymmetrical currents from symmetrical alternating electromotive forces.



J40. -7l3,045. Patented Nov. 4, I902 M. l. PUPIN.

APPARATUS FOR PRODUCING ASYIMETRICAL CURRENTS FRO. SYIIETBlGAL ALTERNATING ELECTBOIOTIVE FORCES.

' (Application filed Sept. 8, 1900.) (No lodom UNITED STATES PATENT OFFICE.

murmur. 'IDYORSKY PUIIN, OF YONKERS, new YORK.

APPARATUS FOR PRODUCING ASYIIETRICAL CURRENTS FROM SYHHETRICM. ALTERNATING ELECTRO- IOTWE FORCES.

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To alt whom it seagcorwcrn:

Be it known that I, Brown Invoasxv Pn- PHI, a citizen of the United Statesoi. America,

residing at Yonkers, county of Westchestor,

' 5 State of New Yorhhave invented certain new and useful Improvements in Apparatus for Producing Asymmetrltml Currents from Symmetrical AlternatingElectromotive Forces, of

which the following is a specification.

l0 An asymmetrical sunset ins periodic current in which the total number ot'coulombs .iiowingjn one direction is greater than the total number flowing iuthe' opposite direction. Such a current will deflect a permaneut magnet and be deflected by it and will produce electrolysis. It is equivalent to the periodicunidirectionsl impulses equal to the ,diiilerenee between the nnmbersof coulombs transmitted in oppealtedinectious.

means for producing an asymmetrical current ins circuit on which is impressed an al-' ternating electrormitive force by opposing to such elects-emotive force an electromotive reaction which is greater is one direction than in the other. I thus construct a circuit which will offer an asymmetrical impedance to a simple harmonic electmmotive force. This electromotive rmetiea an is produced by placing in thecircuit a direct-current generator and a reversible y non-cumulative electrolytic polarizatinn-ocihthe capacity reactance ct which tor the frequency of the electromotive force to be employed is as large as or preferably greater than the other reactance of the circuit. Upon this circuit I snperimpose an alternating electromotive force. The directcurreut generator (say a voltaic cell) and a polarization-cell, which I shall call a simple electrolytic cell (say two platinum electrodes in dilute snlt'uric acid) taken together constitute an asymmetrical electrolytic element whieh'pneessee an alter? nating electromotive reaction that is greater in one direction than in the other. Such an element is the equivalent of a cell (which may also be described, broadly, as an element) which has the property of developing a higher counter electn'omotive force when 50 traversed by neurrent-in one direction than The object of this invention is to provide Plvided sad this application lied September 8, 1900. Serial (Is modelwhen the current is reversed. For example,

it is equivalent to a cell consisting of zinc and a platinum electrode immersed in dilute sulfuric acid. In such a cell. the diflerencc of potential between the two electrodes is not sntlicient to overcome the counter electrometive force due tcdecornposition of water. and hence it generates no current; but it an electromotive force be impressed such a cell opposes agreater counter electromotive force 6c in one direction than in the other. It may be pointed out here that none of these arrangements are emcieut as rectll'lers unless so directed that the electrolytic capacity of the cell is properly adjusted with respect to'thc frequency of the electromotive force, soss'to give the capacity reectance the magnitude hereinafter indicated.

In the accompanying drawings, which form a part of this specification, Figure 1 illustrates my invention as applied to asystem in which a direct-current generator and a reversible non-cumulative polarizer are placed in thecircuit. Fig. 2 shows the arrangement of Fig. 1 as applied to multiplex telegraphy by resonance circuits.

In Fig. 1 a generatorE of'alternating electromotive force of any convenient type is in series with a key F and the primary coil Got atransformer. The key may be, for example, an ordinary telegraph key. Whenever it is closed, an alternating current iiows in the circuit E F G. The circuit may be oi any convenient length, and, if dmired, it may include a telegraphic main line, or the line may be interposed between the cells which are in inductive relation with coils G and ii, respectively, as shown in Fig. 8. A coil 11, forming the secondary coil of the transformer G H, is placed in cincuitin series 0 with a primary cell K, a suitable magnetic circuit-relay closer P, and an electrolytic po' iarizatlon-cell containing two terminal wires, preferably of platinum, which are fused intotwo glass tubes 0 D, so that the ends AB are 5 small'internal resirtanoer The distance apart is conveniently adjusted by heatingand sottening the cross-bar T, Ithen 'placin s thin to sheet. of mica between thcsendi-ot t swine and bringing themiweontact'wlth it sna posite sides while the cross-bar cools and sets,

after whichv the .mica is removed.- The ex-' posed ends of the wires are-then immersed in a suitable electrolytic, as dilute sulfuric acid, and connected to the circuit, as shown, The cell thus formed will be non-storage or. noncnmulative, because the gases will readily bubble away from the small plates, and since,

it is of small 'capacityt-he fullconuter electromotive force is quickly attained. It is capable of developing at its maximum about, two volts connterelectromotive force of po- I tromotive forcedevelope'd in the polarisationv la'rizationf a s5 Thedirect-electromotive-l'orcegenerator'K maybe an ordinary primary cell. It is ob- 1 vion's that either the polarization-cell or the 1 primary cell, or both, may be replaced by batteries of cells in series; but the primary cell or battery should develop an electro'motive force preferably equal to or slightly less. than the maximum counter electromotive force'of the'polarizaticn-cell or battery of cells. The term cell will hereinafter be used to mean 5 either a single cell or a battery of cells.

The primary cell and the polarization-cell together produce no current; but when the key F is closed the alternate electromotive I force is also imposedupon the circuit H A B The counter electromotive force ofthe elem .t-rolytic'cell when charged to its full capacity will be equal to the decomposition value of the electrolyte, and it is assumed that the 5 electrolytic cell develops at its maximum a counter electromotive force about equal to that of the primary cell. Platinum electrodes in dilute sulfuric acid develop a'conn ter electromoti've force oi! about twovolts. Obvi- 30 ously with thesetwo cells alone in the circuit there will be no conduction -current;, but while the plates are receiving a charge what may be called a "condenser-current is Howi'ug. After the plates have been fullycharge'd the two cells will balance each other; butthe s. circuit has this pecularity, speaking gener-' ally, that both the capacity'reactances or the electrolytic cell and the electromotive force' oi the primary battery will oppose an alter- 6: nating electromotive force during one half period and not during the other half period. The capacity of the electrolytic cell can be diminished and its capacity reactance proportionately increased by reducing the size of the plates. If underthe conditions stated, with the electromotive force 0! the primary cell and the counter electromotive force of I visors the electrolytic cell balanced against each .4 that of the apparatus in the circuit) when the i f s in the same directional .thefelcctromotive force-oi the primary cell, and when ido act'sn'c'es, will have also acapsisity reluctance. It, therefore, the-capacity reactance be made large in comparison-with the other taro reactp w. or he alternating electromotive rm,

posed theeircuit, in addition to these tworeances, the current flowing in one direction 1 will be large in comparison with the quantity flowing in the other directiom.

snflicien'tly'large in "order to make the cu'r-. rent consist practically ot a series of nnidb. rectional impulses. It is clear that the values It is only necessary to make the capacity reactsnce of the electromotl've forces need not be in the ratio stated above, but may he in any convenient ratio, so long as the maximum eleccells is less than the-sum o! the other two 'electromotive forces when. these have the same sign. vThen there will-always be obtained an asymmetrical current.

' It is not necessary to have a polarizationother polarization device-having the proper- -cellof the construction given above. Any.

ties heretofore stated maybe substituted for either of the cells herein'described. It must,

however, be a cell the capacity of which is properly proportioned with-respect tothe frequency of the impressed elecjtromotive force,

so as to giveit a capacity reaetance which is of the magnitude described, and for very eilicient rectification the capacity reactance should be, say, as much as one hundred times as large as any-o! the other reactaneesof the circuit. 1 v

This invention is of considerable value in several applications for practical. purposes,

and its application to telegraphy by alternat-' iug currents, and more particularlyto multiplex telegraphy by. resonant receiving-circuits, will now be described. The chief dimculty in usingfalternating currents for telegcnrrent transmitted must, generally speaking, vbe relied on to produce the entire mag- :iitic etlfect inithefreceivligg instrumeriitsfind is magnetiz ng' orce, I ng propor't on g to the square of the magrietising-current, falls ofl rapidly when the current is diminished, as it alwaysis in transmission over long lines." With direct currents, however, the currents transmitted can be acted upon at the receiver by strong msgncticllelds produced independently of these currents, as by powerful permanent magnets or jelectromagnets. Hence by the aid at this invention much stronger efiects can be produced in the receiving appara'tus with a'given impressed alternating electromotive force than is possible without the aid at the invention. 4

raphy is that the magnetizing force of the The application of the invention to telegraphy without employing resonance effects is illustrated in Fig. 1. In this figure the armature P, which is placed between the poles of a powerful permanentmagnct, operates a circuit-closer O, which closes a local circuit in which is a battery M and a sounder N.

A system of multiple telegraphy by resonance receiving-circuits is illustrated in Fig. 2. A long telegraphic line L has at the transmitting end means for impressing on the line independently of each other and simultanecusly or otherwise severa'l alternating currents of diflerentperiodicities. Forinstance, there may be several local transmitting-circuits G F E of Fig. 1 acting upon the line through transformers like G H, the secondary coils being-connected in the line in series. The difierent generators should generate alternating currents of diflerent periodicities. At the receiving end should be several receiving resonance-circuits, like R 8 G, in which R and S are adjustable condensers and G is the primary coil of a tra sformer G' H. Each of these receiving-circui should be tuned to resonance with one of ihe impressed electromotive forces. Connected with each is a circuit H A B K P,.producing an asymmetrical current, and a relay-circuit M N 0, like the similarly-lettered circuits in Fig. 1. The advantages of using a separate circuit H A B K P in addition to the resonance-circuit R S G is that it enables the construction of a resonance-circuit the electromagnetic constants of which are not appreciably effected by the constants of the receiving instrument, since it not be put in the resonance-circuit. I have practiced the invention herein disclosed successfully in recti fying Hertzian oscillations, as well as oscillations of the frequencies produced in ordinary commercial practice. When a circuit is properly adjusted for a given frequency, it will effect even better rectification with all lower frequencies. The converse is of course not true.

I do not in this application claim the herein-described method of producing asymmet-' rical currents, as such method is claimed in my other application, filed January 4, 1898,-

Serial No. 665,650, renewed October 4, 1902, as SerialNo. 125,991, of which application this is-a division.

What I claim, and desire tosecure by Letters Patent of the United States, is-

1. The combination of a circuit, means for impressing an alternating electromotive force thereon and an asymmetrical electrolytic element in the circuit, the capacity reactance of which is properly proportioned with respectto the other reactances of the circuit for the frequency of the alternating electromotive force employed, to reduce the condenser-current to at minimum and to secure efiieient rectification, substantially as described.

2. The combination of acircuit containing a direct-current source and a simple electrolytic cell; with means for impressing upon the circn it an alternating electromotive force, the capacity reactance of the simple electrolytic cell being properly proportioned with respect to the other reactances of the circuit for the frequency of the altcrnatingelectromotive force employed, to reduce the condensercurrent to a minimum, and to secure eflicient rccl'iqcation, substantially as described.

3. n a telegraphic system, the combination of suitable transmitting and receiving devices, means for impressing an alternating electromotive force, and a receiving-circuit provided with means for producing an asymmetrical current, which consists of an electrolytic element, the capacity of which is properly proportioned with respect to the other reactances of the circuit, to secure eflicient rectification, substantially as described.

4. In a telegraphic system, .the combination oi suitable transmitting and receiving devices, means for impressing an alternating electromotive force, and a receiving-circuit, provided with means for producing an asymmetrical current, consisting of a direct-current generator and a simple electrolytic cell, the capacity reactance of the simple electrolytic cell being properly proportioned with re spect to the other reactauees of the circuit for the frequency of the alternatingelectromotive force employed to secure eficient rectification, substantially as described.

5. In a multiplex telegraphic system by resonance-circnits,-the combination of suit? able transmitting and receiving devices,

means for impressing several alternating electromotive forces of different frequencies'independently of each other, and simultaneously or otherwise, and a resonance receivlng circuitprovided with means for producing an asymmetrical current consisting of an asymmetrical electrolytic element, the capacity reactance of whichis properly proportioned with respect to the other reactances of the circuit to secure eflicient rectification, substantially as described.

6. Ina multiplex telegraphic system by resonance-circuits,thecombination of suitable transmitting and receiving devices, means for impressing alternating currents of diiferent frequencies independently of each other, and simultaneously or otherwise, and resonance receiving-circuits provided with means for producing asymmetrical currents, consist ing of a direct-current generator and asimple electrolytic cell, the capacity reactance of the electrolytic cell being properly proportioned with respect to the other reactances of the circuit for the frequency of the alternating electroinotive force to secure eflicient rectification, substantially as described.

Signed by me in New York city this 22d day of August, 1900.

MICHAEL IDVORSKY PUPIN.

Witnesses: Y

SAMUEL W. BALCH, HY H. WHITMAN. 

